Pb2+胁迫对冬凌草种子萌发和幼苗生长的影响

以冬凌草种子为材料,研究铅(Pb2+)溶液(0,135,270,540,1 080 mg·L-1)对冬凌草种子萌发和幼苗生长的影响。结果表明:1低浓度Pb对冬凌草种子萌发无显著影响,Pb质量浓度135 mg·L-1条件下的种子发芽势高于对照,发芽速度快于对照,但差异均不显著;中高质量浓度Pb(270~1 080 mg·L-1)对种子萌发有显著的抑制效应,随着Pb浓度的升高,种子发芽率、发芽势和发芽指数呈递减趋势,均显著低于对照(P<0.05),发芽率比对照低23.97%~55.37%。2低质量浓度Pb(135 mg·L-1)条件下,冬凌草幼苗生长活力指数低于对照,但差异不显著;中高质量浓度Pb(270~1 080 mg·L-1)对幼苗生长有显著抑制效应(P<0.05),胚根长、胚芽长、生物量、生长活力指数均显著低于对照;胚芽和胚根生长受Pb胁迫,其中胚根生长受抑制程度大于胚芽,胚根长比对照低43.09%~100%。3冬凌草Pb富集系数为0.76~2.59,随Pb浓度增高而增大;Pb生物富集是抑制幼苗生长的主要原因。4经拟合模型预测分析,比对照发芽率和生物量鲜重降低10%的Pb临界质量浓度分别为195.18,101.65 mg·L-1。

Effects of Pb2+stress on seed germination & seedling growth of Rabdosia rubescens

The seeds of Rabdosia rubescens were as the materials to research the impacts of different lead(Pb²⁺) concentrations(0, 135, 270, 540, 1 080 mg·L^-1) on seed germination and seedling growth. The results show that: Low concentration of lead had no obvious effect on early germination of the seed, the germination vigor and germination speed were lightly higher but not significantly differed at the level of Pb concentration 135 mg·L^-1 with control group; Mid-high concentration of Pb solution(270-1 080 mg·L^-1) significantly inhibited the seed germination and seedling growth, which reduced the seed germination rate, germination vigor, germination index, embryo root length and shoot length, growth index with increasing of Pb concentrations. There was a inhibitory effect on embryo shoot length and root length at mid-high lead concentrations stress, and stronger inhibitory effect on root, which was more sensitive than shoot to Pb stress(P<0.05). Pb bioaccumulation coefficient(BC) was 0.76-2.59, increased with concentration of Pb; Pb enrichment in seedling mainly caused the growth inhibition. The fitting model predictive analyses show, the critical concentration of Pb, which causes the germination rate and biomass fresh weight reducing 10%, is 195.18,101.65 mg·L^-1.